Page 102 - Polymer-based Nanocomposites for Energy and Environmental Applications

78 Polymer-based Nanocomposites for Energy and Environmental Applications

more interest due to their specific properties such as high latent heat per unit volume,
high thermal conductivity, recyclability, and nonflammability [6].
However, the mean disadvantages of this class are that they are corrosive in nature
[8] and they undergo segregation and supercooling that will affect their phase-change
properties [7]. Finally, eutectics or eutectic mixtures are a mixture of multiple solids,
two or more organic or inorganic compounds in such proportions as freezing and con-
gruent melting [6,11]. This class takes advantage of the combination of good perfor-
mances of both first classes with additional advantages such as the abrupt change in
the phase-change temperature [7]. Table 3.2 presents advantages and disadvantages of
different types of PCMs [8].

3.2.3 Measurement techniques
The techniques employed for the measurement of latent heat of fusion and melting
temperature of PCMs are differential scanning calorimetry (DSC), differential ther-
mal analysis (DTA), and T-history method. It’s validated by Rudd that among all,
the differential scanning calorimetry (DSC) is the most commonly used [12].

Table 3.2 Comparison of different PCM compounds [6-8]

Classification Advantages Disadvantages
Organic PCM l Availability in a large l Low thermal conductivity (around
temperature range 0.2 W/m K)
High heat of fusion Relative large volume change 3
l l
No supercooling Flammability
l l
Noncorrosive
l
Chemically stable
l
Recyclable
l
l Good compatibility with
other materials
Inorganic l High heat of fusion l Supercooling
PCM l High thermal conductivity l Corrosion
(around 0.5 W/m K)
l Low volume change
l Availability in low cost
l Nonflammable
Eutectic PCM l Sharp melting l Limited test data available on their
temperature thermophysical properties
High volumetric thermal
l
storage density